TikTok Says This Supplement Improves Brain Function. Here’s What Experts Say.

ANOTHER WEEK, ANOTHER supplement popping off on social media. This time, everyone is gassing up L-tyrosine.

This trendy supplement also has the backing of health and fitness icons like The Rock and Andrew Huberman. So there must be some legitimacy to it, right?

As Alex Larson, R.D., says, L-tyrosine is having a moment in the supplement world, especially among biohackers and fitness enthusiasts looking for an edge in mental performance. “TikTok trends discuss an L-tyrosine supplement as a treatment for ADHD and depression—though these claims are not backed by strong science.”

Ahead, what you should know about this buzzy supplement and how to determine if L-tyrosine is for you.

What is l-tyrosine?

“L-TYROSINE IS AN amino acid that is naturally occurring and plays a vital role in neurotransmitter production, specifically dopamine, norepinephrine, and epinephrine,” says Trista K. Best, M.P.H., R.D. “It is a non-essential amino acid because it can be created in the body and doesn’t have to be taken in through diet, though it often is.”

L-tyrosine can be found in protein-rich foods like eggs, meat, fish, nuts, soy, and dairy but has become popular in supplement form as well. (When manufactured for supplements, L-tyrosine is extracted from the milk protein casein or produced through fermentation using bacteria.)

Supplementation with L-tyrosine has been a practice for decades, but it has recently become more popular for stress management and cognitive function. It’s being dubbed a nootropic—a class of substances that are said to help with memory, thinking, alertness and other functions of the brain.

“The new interest in nootropics is the basis of its growing popularity, especially among those interested in biohacking to improve their overall health and quality of life,” Best says.

What are the health benefits, and risks, of l-tyrosine?

DON’T GET OVERLY excited by the social media hype. Research on L-tyrosine shows some promise, but more research needs to be done.

Amino acids like L-tyrosine have long been studied for their roles in health and performance, says Larson. “While L-tyrosine has shown beneficial effects in some studies, the evidence is mixed, with some studies unable to show positive effects on cognition.”

“L-tyrosine is a precursor to dopamine, the neurotransmitter that aids in motivation, mood regulation, and pleasure,” says Best. Studies have suggested limited benefit in individuals with low dopamine, like those under chronic stress or experiencing depression, but more research needs to be done to solidify these findings.

According to Kim Yawitz, R.D., your diet typically provides enough of L-tyrosine so supplementing might be unnecessary. It’s worth noting that many of the studies that show some benefit to taking L-tyrosine are in people with chronic health conditions, says Yawitz. Those with phenylketonuria (PKU) can’t eat foods with phenylalanine, another vital amino acid, so doctors sometimes prescribe supplemental L-tyrosine to keep their levels within a normal range.

Some early research shows the supplement may improve physical endurance and performance during exercise or physical activity, says Best. But, again, more research still needs to be done to ensure this benefit.

Are there any risks to taking l-tyrosine?

GENERALLY L-TYROSINE SUPPLEMENTS are considered safe.

It can cause adverse interactions for those taking certain medications, such as hyperthyroidism medication, Best says.

“L-tyrosine is generally tolerated well, but could cause nausea, headaches, and stomach discomfort. High doses may cause overstimulation and lead to insomnia and restlessness,” she says. This is especially true for those who are overly sensitive to stimulants.

As always, you should consult with a trusted healthcare professional before adding a new supplement to your routine.

Should you take L-tyrosine?

THE BOTTOM LINE is that your body is pretty good at keeping L-tyrosine levels in check, making more if you’re running low and getting rid of the excess when your levels are too high, says Yawitz. “This built-in regulation means that there’s not much risk of deficiency in healthy adults—and no need to overload on supplements.”

For those who are still intrigued (and willing to spend the money), Yawitz says that short-term use of L-tyrosine supplements is generally considered to be safe as long as you’re not taking thyroid medications, Parkinson’s drugs, or certain depression medications, “but there’s also not much evidence of its usefulness for healthy adults.”

If you’re thinking about supplementing, speak to a doctor first. A typical dosage should be between 5srcsrc to 2,srcsrcsrc milligrams, according to Best.

“L-tyrosine is absorbed most efficiently on an empty stomach and should be taken 3src–6src minutes prior to eating,” Best says. It is also best taken in the morning or early afternoon to prevent potential sleep disturbances.